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Robin at Caputron dropped me a note to let me know they are now carrying the Foc.us V2 device. Purchased alone, it does not include electrodes, but there is an option to add their ‘starter kit’ which includes the Caputron Universal Strap, Caputron Banana Adapter Cable for Focus Device, and Choice of 2×2 or 3×3 Electrodes. (Use diytdcs at checkout for generous discount). Foc.us V2 Device at Caputron.
If what attracted you to tDCS is all the news (and hype) around the possible benefits, cognitive and otherwise, that tDCS may provide, then I recommend the Foc.us V2 device. It’s had a thorough going over, and apart from the (then included) electrodes, proved to be an amazing piece of gear. tDCS, tACS, tRNS, tPCS in a single sub $300 unit with a software interface!

Foc.us V2

Universal Strap

Banana Plug for Foc.us

Caputron Electrode

Elsewhere on the blog I’ve stated that I recommend the ActivaDose ll device. This is an FDA approved device – it’s NOT FDA approved for tDCS – it’s approval is for use as an Iontophoresis device. The point is that the electronics and workmanship have attained an FDA level of approval. It’s simple and straightforward to use.

The only reason I haven’t recommended other tDCS devices on the market is because I’m not in a position to analyze the quality of their workmanship myself. I recommend the Activadose ll because people looking to experiment with tDCS for the treatment of depression can’t be assumed to have a toolset for determining the mechanical workmanship of an electrical device they’re going to be attaching to their heads! The Activadose ll, an FDA approved device, at least assures the buyer the device itself is of high quality. It’s also more likely to retain some resale value in the event someone decides later on to sell it.

I recommend the Foc.us V2 because of it’s variety of stimulation modes. Folks who are sophisticated enough about neurostimulation to be experimenting with cognitive enhancement would obviously benefit from having the option to test other forms of stimulation that frequently come up in the scientific literature.

But I should also mention that I do have a financial relationship with both Foc.us and Caputron. Years after starting the blog, and only after determining that both companies are providing a high quality service that could benefit DIYtDCS.com readers, I approached them with an interest in attaining a discount for my readers. When you use code diytdcs at checkout at either Foc.us or Caputron you get a discount, and I get a small commission.

Fantastic to have a resource in the community like Nathan who has the background and technical expertise to do a deep dive into assessing a device like the new Foc.us v2. The entire review is a must read but here I’m quoting his analysis of the safety issues.

The foc.us also includes some new safety features designed to reduce the risk of high-current-density induced injuries. The most interesting is a soft voltage limit; while the device can technically output voltages out to 60V, users can specify a lower limit to not exceed. This provides protection if the connection between electrodes and the head starts to fail (due to electrode drying or drift, for instance); rather than increase voltage to the absolute maximum in an attempt to drive the target current over the failing connection (which can result in very high current density through a small patch of skin), the device can be configured to simply allow the current to drop using this limit. Unfortunately, there’s no actual alert that the connection is failing (although this can be deduced from looking at the current monitor during operation) but this still provides a good way to avoid many of the safety issues that the high maximum operating voltage would otherwise entail.

Another important area of safety is the ability of the current regulator to maintain its specified current and voltage outputs under varying conditions. Here I tested the device under two conditions: with relatively stable impedance at varying levels (simulating a typical use case in a person sitting still) and in an “impulse” condition, where impedance changes instantly from very high to very low or vice versa. The purpose of this testing method is to measure the device’s response to temporary very sharp changes in impedance caused by disconnection and reconnection of the electrodes as might occur in the Edge device when used during athletic performance.

Here the foc.us performed perfectly; neither current nor voltage ever significantly exceeded their specified maximums under varying conditions. The response to impulses was particularly impressive, with no significant “overshoot” even at the maximum voltage output.

Very well researched and well-balanced article from Mark Harris at The Economist.

Hardly surprising, then, that DIY brain hackers want in on the action. Christopher Zobrist, a 36-year-old entrepreneur based in Vietnam, is one of them. With little vision he has been registered as blind since birth due to an hereditary condition of his optic nerve that has no established medical treatment. Mr Zobrist read a study of a different kind of transcranial stimulation (using alternating current) that had helped some glaucoma patients in Germany recover part of their vision. Despite neither the condition nor the treatment matching his own situation, Mr Zobrist decided to try tDCS in combination with a visual training app on his tablet computer. He quickly noticed improvements in his distance vision and perception of contrast. “After six months, I can see oncoming traffic two to three times farther away than before, which is very helpful when crossing busy streets,” he says.
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Equally troublesome is a meta-analysis of the cognitive and behavioural effects on healthy adults that Mr Horvath subsequently carried out. As before, he included only the most reliable studies: those with a sham control group and replicated by other researchers. It left 200 studies claiming to have discovered beneficial effects on over 100 activities such as problem solving, learning, mental arithmetic, working memory and motor tasks. After his meta-analysis, however, tDCS was found to have had no significant effect on any of them.

If tDCS alters neither the physiology of the brain nor how it performs, thinks Mr Horvath, then evidence suggests it is not doing anything at all. Marom Bikson, a professor of biomedical engineering at City University of New York, disagrees. “I can literally make you fall on your butt using the ‘wrong’ type of tDCS,” he says. Dr Bikson thinks the biggest challenge for tDCS is optimising techniques, such as the dose.